Organic light emitting device, method of manufacturing the same, and method of forming organic layer

ABSTRACT

An organic light emitting device that has improved lifespan properties by improving the characteristics of an interface between at least one of a red emissive layer, a green emissive layer or a blue emissive layer, and an electron transport layer, and a method of manufacturing the organic light emitting device.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This is a divisional application of U.S. patent application Ser. No.11/967,594 filed Dec. 31 2007 now U.S. Pat. No. 7,535,167 which claimspriority to and the benefit of Korean Patent Application No.10-2007-0017086, filed on Feb. 20, 2007, in the Korean IntellectualProperty Office, the entire content of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic light emitting device, amethod of manufacturing the same, and a method of forming an organiclayer.

2. Description of the Related Art

An organic light emitting device is a self-emitting device that has awide viewing angle, excellent contrast, and quick response time. Also, alot of research has been conducted on organic light emitting devicesbecause of their lower driving voltages and quicker response times, andbecause they can realize multicolor images.

A conventional organic light emitting device has a stacked structure inthe form of an anode/emissive layer/cathode structure. A hole injectionlayer, a hole transport layer, and an electron injection layer may beadditionally formed between the anode and the emissive layer or betweenthe emissive layer and the cathode to form an anode/hole transportlayer/emissive layer/cathode structure, an anode/hole transportlayer/emissive layer/electron injection layer/cathode structure, or thelike. Korean Patent Publication No. 10-2005-0040960, the entire contentof which is incorporated herein by reference, discloses such an organiclight emitting device.

However, a conventional organic light emitting device does not havesatisfactory lifespan properties, and thus there is a need for furtherimprovement.

SUMMARY OF THE INVENTION

Aspects of embodiments of the present invention are directed toward anorganic light emitting device that has long lifespan by improving thecharacteristics of an interface between an emissive layer (e.g., atleast one of a red emissive layer, a green emissive layer, or a blueemissive layer) and an electron transport layer, a method ofmanufacturing the organic light emitting device, and a method of formingan organic layer having a multilayer structure.

An embodiment of the present invention provides an organic lightemitting device that includes: a substrate; a first electrode on thesubstrate; a second electrode facing the first electrode; and an organiclayer between the first electrode and the second electrode, andincluding an emissive layer and an electron transport layer. Here, theemissive layer includes: a red emissive layer, a green emissive layer,and a blue emissive layer. The electron transport layer includes: afirst electron transport layer including at least one of a first layeron the red emissive layer and having substantially the same pattern asthat of the red emissive layer, a second layer on the green emissivelayer and having substantially the same pattern as that of the greenemissive layer, or a third layer on the blue emissive layer and havingsubstantially the same pattern as that of the blue emissive layer; and asecond electron transport layer on the first electron transport layer asa common layer with respect to red, green, and blue sub-pixels.

In one embodiment, the first electron transport layer includes the firstlayer, the second layer, and the third layer.

In one embodiment, the first layer is on the red emissive layer, and thesecond electron transport layer is on the first layer; the second layeris on the green emissive layer, and the second electron transport layeris on the second layer; and the third layer is on the blue emissivelayer, and the second electron transport layer is on the third layer.

In one embodiment, the thicknesses of the first layer, the second layer,and the third layer are substantially identical to one another.

In one embodiment, a thickness ratio of the first layer to the secondelectron transport layer, a thickness ratio of the second layer to thesecond electron transport layer, and a thickness ratio of the thirdlayer to the second electron transport layer are in the range from about1:9 to about 4:6.

In one embodiment, the organic layer further includes at least one of ahole injection layer, a hole transport layer, a hole blocking layer, oran electron injection layer.

Another embodiment of the present invention provides a method ofmanufacturing an organic light emitting device that includes: forming afirst electrode on a substrate; forming on the first electrode anorganic layer including an emissive layer and an electron transportlayer; and forming a second electrode on the organic layer, wherein theemissive layer includes: a red emissive layer, a green emissive layer,and a blue emissive layer, wherein the electron transport layersincludes: a first electron transport layer including at least one of afirst layer on the red emissive layer and having substantially the samepattern as that of the red emissive layer, a second layer on the greenemissive layer and having substantially the same pattern as that of thegreen emissive layer, and a third layer on the blue emissive layer andhaving substantially the same pattern as that of the blue emissivelayer; and a second electron transport layer on the first electrontransport layer as a common layer with respect to red, green, and bluesub-pixels, and wherein the forming the organic layer includes: a)forming the emissive layer and the first electron transport layer, theforming the emissive layer and the first electron transport layerincluding at least one of forming the red emissive layer and thenforming the first layer in a first deposition chamber for forming thered emissive layer; forming the green emissive layer and then formingthe second layer in a second deposition chamber for forming the greenemissive layer; or forming the blue emissive layer and then forming thethird layer in a third deposition chamber for forming the blue emissivelayer, and b) forming the second electron transport layer on the firstelectron transport layer as a common layer with respect to the red,green, and blue sub-pixels.

In one embodiment, the first layer is formed utilizing a mask forforming the red emissive layer.

In one embodiment, the second layer is formed utilizing a mask forforming the green emissive layer.

In one embodiment, the third layer is formed utilizing a mask forforming the blue emissive layer.

In one embodiment, the first layer and the second electron transportlayer are sequentially formed on the red emissive layer, the secondlayer and the second electron transport layer are sequentially formed onthe green emissive layer, and the third layer and the second electrontransport layer are sequentially formed on the blue emissive layer.

Another embodiment of the present invention provides a method of formingan organic layer that includes: forming a first organic layer formed ofa first organic material in a first chamber; forming on the firstorganic layer in the first chamber a second organic layer formed of asecond organic material; and forming on the second organic layer in asecond chamber a third organic layer formed of the second organicmaterial.

In the forming of the organic layers, the first, second, and thirdorganic layers are disposed between a pair of electrodes of an organiclight emitting device.

The organic light emitting device according to an embodiment asdescribed above has improved lifespan properties.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, together with the specification, illustrateexemplary embodiments of the present invention, and, together with thedescription, serve to explain the principles of the present invention.

FIG. 1 is a schematic cross-sectional view of an organic light emittingdevice according to an embodiment of the present invention;

FIGS. 2A, B, C, D, E, F, and G are diagrams illustrating a process offorming an emissive layer and an electron transport layer of an organiclight emitting device according to an embodiment of the presentinvention; and

FIGS. 3A, B, and C are diagrams illustrating a method of forming anorganic layer according to an embodiment of the present invention.

DETAILED DESCRIPTION

In the following detailed description, only certain exemplaryembodiments of the present invention are shown and described, by way ofillustration. As those skilled in the art would recognize, the inventionmay be embodied in many different forms and should not be construed asbeing limited to the embodiments set forth herein. Also, in the contextof the present application, when an element is referred to as being “on”another element, it can be directly on the another element or beindirectly on the another element with one or more intervening elementsinterposed therebetween. Like reference numerals designate like elementsthroughout the specification.

FIG. 1 is a schematic cross-sectional view of an organic light emittingdevice 10 according to an embodiment of the present invention.

Referring to FIG. 1, the organic light emitting device 10 includes asubstrate 11, first electrodes 12, a hole injection layer 16 and a holetransport layer 18. In addition, a red emissive layer 22R, a greenemissive layer 22G, and a blue emissive layer 22B are patterned on thehole transport layer 18. A first electron transport layer 24 and asecond electron transport layer 25 are sequentially formed on theemissive layers 22R, 22G, and 22B. The first electron transport layer 24includes: a first layer 24R that is formed on the red emissive layer 22Rand has the same (or substantially the same) pattern as that of the redemissive layer 22R; a second layer 24G that is formed on the greenemissive layer 22G and has the same (or substantially the same) patternas that of the green emissive layer 22G; and a third layer 24B that isformed on the blue emissive layer 22B and has the same (or substantiallythe same) pattern as that of the blue emissive layer 22B. The secondelectron transport layer 25 is formed as a common layer with respect tored, green, and blue sub-pixels (R, G and B). An electron injectionlayer 26 and a second electrode 28 are formed on the second electrontransport layer 25.

In FIG. 1, the substrate 11 can be any suitable substrate used inconventional organic light-emitting devices such as a glass substrate ora transparent plastic substrate, which has superior mechanical strength,thermostability, transparency, surface smoothness, ease of treatment,and waterproof properties. Although not shown in FIG. 1, a planarizationlayer, an insulating layer, and the like can be further formed on thesubstrate 11.

The first electrodes 12 are formed on the substrate 11. The firstelectrodes 12 can be patterned according to red, green and bluesub-pixels (R, G, B) as described in FIG. 1, and may each be an anode ora cathode. The first electrodes 12 can be transparent, semitransparent,or reflexive, and formed of ITO, IZO, SnO₂, ZnO, Al, Ag, Mg or the like,but the present invention is not limited thereto. In addition, varioussuitable modifications are possible such that a structure having atleast two layers can be obtained using at least two different materials.

Insulating layers 14 are formed on both ends (or end portions) of thefirst electrodes 12 and the substrate 11. The insulating layers 14 canbe formed of a suitable insulating material that may be an inorganicmaterial, such as SiO₂, SiN_(x) or the like, and/or an organic material,such as a polyimide-based resin, an acryl-based resin or the like.

The hole injection layer 16 is formed on the first electrodes 12. Thehole injection layer 16 can be formed as a common layer with respect tored, green and blue sup pixels (R, G, B) as illustrated in FIG. 1. Inaddition, although not illustrated in FIG. 1, various suitablemodifications are possible such that the hole injection layer 16 can bepatterned according to the red, green, and blue sub-pixels (R, G, B).

The hole injection layer 16 can be formed using various suitable methodssuch as vacuum deposition, spin coating, casting, Langmuir Blodgett(LB), or the like.

When vacuum deposition is used to form the hole injection layer 16, thedeposition conditions may vary according to the compound used and thestructure and thermal properties of the hole injection layer 16 to beformed. In general, however, the conditions for vacuum deposition may bein a temperature ranging from 100 to 500° C., a pressure ranging from10⁻⁸ to 10⁻³ torr, a deposition speed ranging from 0.01 to 100 Å/sec,and a layer thickness ranging from 10 Å to 5 μm.

When spin coating is used to form the hole injection layer 16, thecoating conditions may vary according to the compound used, and thestructure and thermal properties of the hole injection layer 16 to beformed. In general, however, the conditions for spin coating may be in acoating speed ranging from about 2000 to about 5000 rpm, and a heattreatment temperature ranging from about 80 to about 200° C. to removethe solvent after coating.

More particularly, the hole injection layer 16 may be formed of anysuitable hole injection materials. Examples of the hole injectionmaterials include phthalocyanine compounds such as copperphthalocyanine,which is disclosed in U.S. Pat. No. 4,356,429 and the entire content ofwhich is incorporated herein by reference, star-burst type aminederivatives such as TCTA, m-MTDATA, and m-MTDAPB, which are disclosed inAdvanced Material, 6, p. 677 (1994) and the entire content of which isincorporated herein by reference, or soluble conductive polymers such asPani/DBSA (Polyaniline/Dodecylbenzenesulfonic acid) or PEDOT/PSS (Poly(3,4-ethylenedioxythiophene)/Poly (4-styrenesulfonate), Pani/CSA(Polyaniline/Camphor sulfonicacid) or PANI/PSS (Polyaniline)/Poly(4-styrenesulfonate)), but are not limited thereto.

The thickness of the hole transport layer 18 may be between 10-200 nm,and, in one embodiment, be between 20-150 nm. The thickness of the holetransport layer 18 may be selected within these ranges taking intoconsideration the driving voltage properties, manufacturing time, andmanufacturing cost.

The hole transport layer 18 is formed on the hole injection layer 16.The hole transport layer 18 can be formed using various suitable methodssuch as vacuum deposition, spin coating, casting, Langmuir Blodgett(LB), or the like. When vacuum deposition or spin coating is used toform the hole transport layer 18, the deposition or coating conditionsmay vary according to the compound used. In general, however, thedeposition or coating conditions used to form the hole injection layer16 are the same (or substantially the same) as those for forming thehole transport layer 18.

The hole transport layer 18 can be formed as a common layer with respectto red, green and blue sup pixels (R, G, B) as illustrated in FIG. 1. Inaddition, although not illustrated in FIG. 1, various suitablemodifications are possible such that the hole transport layer 18 can bepatterned according to the red, green and blue sub-pixels (R, G, B).

More particularly, the hole transport layer 18 may be formed of anysuitable hole transport materials. Examples of the hole transportmaterials include a carbazole derivative, such as N-phenylcarbazole orpolyvinylcarbazole; an amine derivative having an aromatic fused ringsuch asN,N′-bis(3-methylphenyl-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD)or N,N′-di(naphthalene-1-yl)-N,N′-diphenylbenzidine (α-NPD); or thelike.

Each of the red emissive layer 22R, the green emissive layer 22G, andthe blue emissive layer 22B is patterned on the hole transport layer 18according to the red, green and blue sub-pixels (R, G, B), respectively.

The red emissive layer 22R, the green emissive layer 22G, and the blueemissive layer 22B can be formed of various suitable emitting materials,or suitable host and dopant materials. The dopant materials can be anysuitable fluorescent dopants and/or phosphorescent dopants.

Examples of the host materials include Alq₃, CBP(4,4′-N,N′-dicarbazole-biphenyl), PVK(poly(n-vinylcarbazole)), distyrylarylene(DSA) and the like, but are not limited thereto.

Examples of the dopant materials include PtOEP, Ir(piq)₃, Btp₂Ir(acac),DCJTB and the like as a red dopant, but are not limited thereto.

In addition, examples of the dopant materials include Ir(ppy)₃(ppy=phenylpyridine), Ir(ppy)₂(acac), Ir(mpyp)₃, C545T and the like as agreen dopant, but are not limited thereto.

Also, examples of the dopant materials include F₂Irpic, (F₂ppy)₂Ir(tmd),Ir(dfppz)₃, ter-fluorene and the like as a blue dopant, but are notlimited thereto.

The amount of the dopant may range from 0.1 to 20 parts by weight basedon 100 parts by weight of the total weight of the host and the dopant,and, in one embodiment, may range from 0.5 to 15 parts by weight. Whenthe amount of the dopant is within these ranges, a concentrationquenching phenomenon can be substantially limited.

The thickness of the red emissive layer 22R, the green emissive layer22G and the blue emissive layer 22B may be in the range from about 5 toabout 100 nm, and, in one embodiment, may be in the range from 10 to 50nm. When the thickness of the red emissive layer 22R, the green emissivelayer 22G and the blue emissive layer 22B is within the ranges describedabove, excellent emitting properties can be obtained.

The first electron transport layer 24 and the second electron transportlayer 25 are formed on the red emissive layer 22R, the green emissivelayer 22G, and the blue emissive layer 22B.

The first electron transport layer 24 includes: a first layer 24R thatis formed on the red emissive layer 22R and has the same (orsubstantially the same) pattern as that of the red emissive layer 22R; asecond layer 24G that is formed on the green emissive layer 22G and hasthe same (or substantially the same) pattern as that of the greenemissive layer 22G; and a third layer 24B that is formed on the blueemissive layer 22B and has the same (or substantially the same) patternas that of the blue emissive layer 22B.

In addition, the second electron transport layer 25 is formed on thefirst electron transport layer 24 including the first layer 24R, thesecond layer 24G and the third layer 24B. The second electron transportlayer 25 is formed as a common layer with respect to red, green and bluesub-pixels (R, G and B) as illustrated in FIG. 1.

Therefore, in the organic light emitting device 10, the first layer 24Rand the second electron transport layer 25 are sequentially formed onthe red emissive layer 22R in the red sub-pixel R, the second layer 24Gand the second electron transport layer 25 are sequentially formed onthe green emissive layer 22G in the green sub-pixel G, and the thirdlayer 24B and the second electron transport layer 25 are sequentiallyformed on the blue emissive layer 22B in the blue sub-pixel B.

The first electron transport layer 24, including the first layer 24R,the second layer 24G and the third layer 24B, and the second electrontransport layer 25, can be composed of any suitable electron transportmaterial. The first electron transport layer 24 and the second electrontransport layer 25 can be formed using vacuum deposition. The depositionconditions may vary according to the compound used. In general, however,the deposition conditions used to form the hole injection layer 16 areused to form the first electron transport layer 24 and the secondelectron transport layer 25. The material for forming the first electrontransport layer 24 and the second electron transport layer 25 stablytransports electrons injected from a cathode. Examples of the materialfor forming the first electron transport layer include suitablematerials such as quinoline derivatives, and, in one embodiment, thematerial for forming the first electron transport layer includestris(8-quinolinorate)aluminium (Alq₃), TAZ, Balq or the like, but is notlimited thereto.

The thicknesses of the first layer 24R, the second layer 24G and thethird layer 24B can be equal to one another or different from oneanother.

Also, a thickness ratio of the first layer 24R to the second electrontransport layer 25, a thickness ratio of the second layer 24G to thesecond electron transport layer 25, and a thickness ratio of the thirdlayer 24B to the second electron transport layer 25 may be in the rangefrom about 1:9 to about 4:6 (or from 1:9 to 4:6), and, in oneembodiment, may be in the range from about 2:8 to about 3:7 (or from 2:8to 3:7). That is, the thickness of the first layer 24R, the thickness ofthe second layer 24G or the thickness of the third layer 24B may be inthe range from about 10 to about 40% (or from 10 to 40%) with respect tothe total thickness of all the electron transport layers. In oneembodiment, the thickness of the first layer 24R, the thickness of thesecond layer 24G or the thickness of the third layer 24B may be in therange from about 20 to about 30% (or from 20 to 30%) with respect to thetotal thickness of all the electron transport layers. When the thicknessratio of the first, second, and third layers 24R, 24G, and 24B to thesecond electron transport layer 25 is within these ranges, an organiclight emitting device 10 with improved lifespan can be obtained.

More particularly, a method of forming the red emissive layer 22R, thegreen emissive layer 22G, the blue emissive layer 22B, the firstelectron transport layer 24, and the second electron transport layer 25will now be described in more detail with reference to FIGS. 2A through2G.

Referring to FIG. 2A, first, in a chamber 41 for forming a red emissivelayer, a red emitting material is deposited on the hole transport layer18 using a mask 32R in order to form the red emissive layer 22R.

Referring to FIG. 2B, in the chamber 41 for forming the red emissivelayer 22R, an electron transporting material is then deposited on thered emissive layer 22R using the mask 32R in order to form the firstlayer 24R. Thus, the first layer 24R is formed on the red emissive layer22R and has the same (or substantially the same) pattern as that of thered emissive layer 22R.

Then, referring to FIG. 2C, in a chamber 43 for forming a green emissivelayer, a green emitting material is deposited on the hole transportlayer 18 using a mask 32G for forming a green emissive layer 22G.

Thereafter, referring to FIG. 2D, in the chamber 43 for forming a greenemissive layer 22G, an electron transporting material is deposited onthe green emissive layer 22G using the mask 32G in order to form thesecond layer 24G. Thus, the second layer 24G is formed on the greenemissive layer 22G and has the same (or substantially the same) patternas that of the green emissive layer 22G.

Next, referring to FIG. 2E, in a chamber 45 for forming a blue emissivelayer, a blue emitting material is deposited on the hole transport layer18 using a mask 32B in order to form the blue emissive layer 22B.

Referring to FIG. 2F, in the chamber 45 for forming a blue emissivelayer 22B, an electron transporting material is then deposited on theblue emissive layer 22B using the mask 32B in order to form the thirdlayer 24B. Thus, the third layer 24B is formed on the blue emissivelayer 22B and has the same (or substantially the same) pattern as thatof the blue emissive layer 22B.

Referring to FIG. 2G, in a chamber 47 for forming an electron transportlayer, an electron transporting material is deposited using an open mask35 to form the second electron transport layer 25, which is a commonlayer with respect to red, green and blue sub-pixels.

In the organic light emitting device illustrated in FIG. 1, after thered emissive layer 22R, the green emissive layer 22G, and the blueemissive layer 22B are formed, the electron transporting materials arethen (or immediately) deposited on the emissive layers 22R, 22G, and 22Bin the same chamber in order to form the first layer 24R, the secondlayer 24G, and the third layer 24B. Therefore, impurities such asmoisture or the like do not substantially infiltrate into an interfacebetween the red emissive layer 22R and the first layer 24R, an interfacebetween the green emissive layer 22G and the second layer 24G, and aninterface between the blue emissive layer 22B and the third layer 24B.As a result, the organic light emitting device 10 can have significantlyimproved lifespan properties.

According to a conventional method of manufacturing an organic lightemitting device, red, green and blue emissive layers are formed inseparate chambers, and then moved into a chamber for forming an electrontransport layer. Thus, there is a problem in that while moving theemissive layers into another chamber, moisture existing in a depositionchamber can contact the surfaces of the red, green and blue emissivelayers. Accordingly, impurities such as water or the like can infiltrateinto an interface between red emissive layer and the electron transportlayer, an interface between the green emissive layer and the electrontransport layer, and an interface between the blue emissive layer andthe electron transport layer, thereby resulting in a reduction in thelifespan of the conventional organic light emitting device.

However, in the organic light emitting device 10 illustrated in FIG. 1,the red emissive layer 22R is formed and then a part of an electrontransport layer, that is, the first layer 24R, is immediately formedthereon in the same chamber, the green emissive layer 22G is formed andthen a part of an electron transport layer, that is, the second layer24G, is immediately formed thereon in the same chamber, and then theblue emissive layer 22B is formed and then a part of an electrontransport layer, that is, the third layer 24B, is immediately formedthereon in the same chamber. Therefore, impurities such as water or thelike do not (or do not substantially) infiltrate into an interfacebetween red emissive layer 22R and the electron transport layer (i.e.,the first layer 24R), an interface between the green emissive layer 22Gand the electron transport layer (i.e., the second layer 24G), and aninterface between the blue emissive layer 22B and the electron transportlayer (i.e., the third layer 24B), thereby resulting in an increase inthe lifespan of the organic light emitting device 10 illustrated in FIG.1.

Also, the organic light emitting device 10 illustrated in FIG. 1includes (or necessarily includes) the second electron transport layer25 that is formed on the first electron transport layers 24 as a commonlayer with respect to red, green and blue sub-pixels (R, G, and B). Thatis, in the chamber 41 for forming a red emissive layer, the chamber 43for forming a green emissive layer, and the chamber 45 for forming ablue emissive layer, not all of the electron transport layers are notformed, but only a part of the electron transport layers (i.e., only thefirst electron transport layer 24 of FIG. 1) is formed. Moreparticularly, referring to FIG. 2G, a ratio of the thickness d₁ of thefirst electron transport layer 24 to the thickness d₂ of the secondelectron transport layer 25 may be in the range from about 1:9 to about4:6 (or from 1:9 to 4:6), and, in one embodiment, from about 2:8 toabout 3:7 (from 2:8 to 3:7), wherein the thicknesses of the first layer24R, the second layer 24G, and the third layer 24B are equal (orsubstantially identical) to one another. By separately forming theelectron transport layers in this way, mass production yield can beimproved. In addition, the first electron transport layer 24 protectsthe emissive layers 22R, 22G and 22B when the second electron transportlayer 25 is formed, and thus the organic light emitting device 10 canhave improved lifespan properties.

The electron injection layer 26 that easily injects electrons from acathode is then formed on the second electron transport layer 25. Theelectron injection layer 26 can be formed using various suitable methodssuch as vacuum deposition, spin coating, casting, or the like. Whenvacuum deposition or spin coating is used, the deposition or coatingconditions may vary according to the compound used. In general, however,the deposition or coating conditions used to form the hole injectionlayer 16 are to the same (or substantially the same) as those forforming the electron injection layer 26. The electron injection layer 26is also formed as a common layer with respect to red, green and bluesub-pixels (R, G, and B), as illustrated in FIG. 1.

The electron injection layer 26 can include any suitable materials suchas LiF, NaCl, CsF, Li₂O, BaO, or the like. The thickness of the electroninjection layer 26 may be in the range from about 0.1 to about 10 nm,and, in one embodiment, in the range from 0.2 to 5 nm. When thethickness of the electron injection layer 26 is within the rangesdescribed above, an organic light emitting device with excellentelectron injecting ability and driving voltage characteristics can bemanufactured.

In addition, a second electrode 28 is formed on the electron injectionlayer 26. The second electrode 28 can be formed using vacuum deposition,sputtering, or the like, and may be a cathode or anode. Examples of ametal used to form the second electrode include a metal having a lowwork function, alloys, electrical-conductive compounds, and mixturesthereof. Examples of the metal used to form the second electrode includeLi, Mg, Al, Al—Li, Ca, Mg—In, Mg—Ag, and the like. In addition, varioussuitable modifications are possible such that a structure having atleast two layers can be obtained using at least two different materials.

The organic light emitting device 10 according to an embodiment of thepresent invention has been described with reference to FIG. 1, but thepresent invention is not limited thereto and the organic light emittingdevice can have various suitable structures. For example, when anemissive layer of the organic light emitting device according to anembodiment of the present invention includes a phosphorescent dopant, ahole blocking layer (HBL) can be formed on the emissive layer in orderto prevent (or reduce) triplet excitons or holes from being diffusedinto the electron transport layer. In addition, in the organic lightemitting device 10 of FIG. 1, the first electron transport layer 24 canhave various suitable structures so that it can include all of the firstlayer 24R, the second layer 24G, and the third layer 24B, or can includeat least only one layer selected therefrom (as desired or necessary).

As described above, the method of manufacturing the organic lightemitting device according to an embodiment of the present inventionincludes: forming a first electrode on a substrate; forming an organiclayer including an emissive layer and an electron transport layer on thefirst electrode; and forming a second electrode on the organic layer.Here, in one embodiment, the emissive layer includes a red emissivelayer, a green emissive layer, and a blue emissive layer. The electrontransport layer includes a first electron transport layer including: atleast one of a first layer that is formed on the red emissive layer andhas the same (or substantially the same) pattern as that of the redemissive layer; a second layer that is formed on the green emissivelayer and has the same (or substantially the same) pattern as that ofthe green emissive layer; and a third layer that is formed on the blueemissive layer and has the same (or substantially the same) pattern asthat of the blue emissive layer, and a second electron transport layerthat is formed on the first electron transport layer as a common layerwith respect to red, green and blue sub-pixels.

In the method of manufacturing the organic light emitting deviceaccording to one embodiment of the present invention, the forming of theorganic layer includes: (1) the forming of the emissive layer and thefirst electron transport layer (e.g., in one embodiment, the forming ofthe emissive layer and the first electron transport layer includes:forming a red emissive layer and then forming the first layer in a firstdeposition chamber for forming the red emissive layer, forming a greenemissive layer and then forming the second layer in a second depositionchamber for forming the green emissive layer, and/or forming a blueemissive layer and then forming the third layer in a third depositionchamber for forming the blue emissive layer), and (2) forming a secondelectron transport layer that is formed on the first electron transportlayer as a common layer with respect to red, green and blue sub-pixels.

The forming of the organic layer can further include forming at leastone of a hole injection layer, a hole transport layer, a hole blockinglayer or an electron injection layer.

Also, an embodiment of the present invention provides a method offorming an organic layer, including: forming a first organic layer of afirst organic material in a first chamber; forming a second organiclayer of a second organic material on the first organic layer in thefirst chamber; and a third organic layer of a second organic material onthe second organic layer in a second chamber.

FIGS. 3A through 3C are diagrams illustrating a method of forming anorganic layer according to an embodiment of the present invention.

Referring to FIG. 3A, a first organic material is deposited on asubstrate 51 using a mask 61 for forming a first organic layer 53 of afirst organic material in a first chamber 71.

Referring to FIG. 3B, a second organic material is then deposited on thefirst organic layer 53 using the mask 61 for forming a first organiclayer 53 in the first chamber 71 in order to form a second organic layer55 a of a second organic material.

Referring to FIG. 3C, a second organic material is deposited on thesecond organic layer 55 a using a mask 63 forming a third organic layer55 b of a second organic material in a second chamber 73.

In this way, impurities, such as moisture or the like, do not infiltrate(or do not substantially infiltrate) into an interface between the firstorganic layer 53 and the second organic layer 55 a that are formed ofdifferent materials.

The forming of the organic layer as described above can be particularlyadvantageous in the case of the organic layer that is disposed between apair of electrodes of the organic light emitting device. In general, theorganic layer of an organic light emitting device can have a multi-layerstructure including different materials. In this case, each layerincluding different materials can be formed in different chambers.However, there is a problem in that during the waiting time for thetransfer between chambers, impurities such as moisture or the like caninfiltrate into an interface between layers including differentmaterials, thereby resulting in a reduction in the lifespan of theorganic light emitting device. However, according to the forming of theorganic layer as described above, when layers (that is, the firstorganic layer 53 and the second organic layer 55 a) including differentmaterials are formed as described with reference to FIGS. 3A and 3B,chamber transfer is not required, but when layers (that is, the secondorganic layer 55 a and the third organic layer 55 b) including the same(or substantially the same) materials are formed as described withreference to FIGS. 3B and 3C, chamber transfer is performed. Therefore,an organic light emitting device having improved lifespan can bemanufactured.

More particularly, the first organic material can be a hole injectingmaterial, the first organic layer can be a hole injection layer, thesecond organic material can be a hole transporting material, and thesecond organic layer and the third organic layer can be a hole transportlayer.

In addition, the first organic material can be a hole transportingmaterial, the first organic layer can be a hole transport layer, thesecond organic material can be a red emitting material, and the secondorganic layer and the third organic layer can be a red emissive layer.

In addition, the first organic material can be a hole transportingmaterial, the first organic layer can be a hole transport layer, thesecond organic material can be a green emitting material, and the secondorganic layer and the third organic layer can be a green emissive layer.

In addition, the first organic material can be a hole transportingmaterial, the first organic layer can be a hole transport layer, thesecond organic material can be a blue emitting material, and the secondorganic layer and the third organic layer can be a blue emissive layer.

In addition, the first organic material can be a red emitting material,the first organic layer can be a red emissive layer, the second organicmaterial can be an electron transporting material, and the secondorganic layer and the third organic layer can be an electron transportlayer.

In addition, the first organic material can be a green emittingmaterial, the first organic layer can be a green emissive layer, thesecond organic material can be an electron transporting material, andthe second organic layer and the third organic layer can be an electrontransport layer.

In addition, the first organic material can be a blue emitting material,the first organic layer can be a blue emissive layer, the second organicmaterial can be an electron transporting material, and the secondorganic layer and the third organic layer can be an electron transportlayer.

In addition, the first organic material can be an electron transportingmaterial, the first organic layer can be an electron transport layer,the second organic material can be an electron injecting material, andthe second organic layer and the third organic layer can be an electroninjection layer. The forming of the organic layers as described abovecan be used for forming each layer in the structure of organic layers ofan organic light emitting device according to embodiments of the presentinvention.

As described above, the organic light emitting device according to anembodiment of the present invention has significantly improved lifespanproperties by improving the characteristics of an interface between anemissive layer and an electron transport layer.

While the present invention has been described in connection withcertain exemplary embodiments, it is to be understood that the inventionis not limited to the disclosed embodiments, but, on the contrary, isintended to cover various modifications and equivalent arrangementsincluded within the spirit and scope of the appended claims, andequivalents thereof.

1. A method of manufacturing an organic light emitting device, themethod comprising: forming a first electrode on a substrate; forming onthe first electrode an organic layer comprising an emissive layer and anelectron transport layer; and forming a second electrode on the organiclayer, wherein the emissive layer comprises: a red emissive layer, agreen emissive layer, and a blue emissive layer, wherein the electrontransport layer comprises: a first electron transport layer comprisingat least one of a first layer on the red emissive layer and havingsubstantially the same pattern as that of the red emissive layer, asecond layer on the green emissive layer and having substantially thesame pattern as that of the green emissive layer, and a third layer onthe blue emissive layer and having substantially the same pattern asthat of the blue emissive layer; and a second electron transport layeron the first electron transport layer as a common layer with respect tored, green, and blue sub-pixels, and wherein the forming the organiclayer comprises: a) forming the emissive layer and the first electrontransport layer, the forming the emissive layer and the first electrontransport layer comprising at least one of forming the red emissivelayer and then forming the first layer in a same first depositionchamber for forming the red emissive layer; forming the green emissivelayer and then forming the second layer in a same second depositionchamber for forming the green emissive layer; or forming the blueemissive layer and then forming the third layer in a same thirddeposition chamber for forming the blue emissive layer, and b) formingthe second electron transport layer in a fourth deposition chamber onthe first electron transport layer as a common layer with respect to thered, green, and blue sub-pixels.
 2. The method of claim 1, wherein thefirst layer is formed utilizing a mask for forming the red emissivelayer.
 3. The method of claim 1, wherein the second layer is formedutilizing a mask for forming the green emissive layer.
 4. The method ofclaim 1, wherein the third layer is formed utilizing a mask for formingthe blue emissive layer.
 5. The method of claim 1, wherein the firstlayer and the second electron transport layer are sequentially formed onthe red emissive layer, the second layer and the second electrontransport layer are sequentially formed on the green emissive layer, andthe third layer and the second electron transport layer are sequentiallyformed on the blue emissive layer.
 6. The method of claim 1, wherein thethicknesses of the first layer, the second layer and the third layer aresubstantially identical to one another.
 7. The method of claim 1,wherein a thickness ratio of the first layer to the second electrontransport layer, a thickness ratio of the second layer to the secondelectron transport layer, and a thickness ratio of the third layer tothe second electron transport layer are in the range from about 1:9 toabout 4:6.
 8. The method of claim 1, wherein the forming of organiclayers further comprises forming at least one of a hole injection layer,a hole transport layer, a hole blocking layer, or an electron injectionlayer.
 9. A method of forming an organic layer, the method comprising:forming a first organic layer formed of a first organic material in afirst chamber; forming on the first organic layer in the same firstchamber a second organic layer formed of a second organic material; andforming on the second organic layer in a second chamber a third organiclayer formed of the second organic material.
 10. The method of claim 9,wherein the first, second, and third organic layers are disposed betweena pair of electrodes of an organic light emitting device.
 11. The methodof claim 10 , wherein the first organic material is a hole injectingmaterial, the first organic layer is a hole injection layer, the secondorganic material is a hole transporting material, and the second organiclayer and the third organic layer are a hole transport layer.
 12. Themethod of claim 10, wherein the first organic material is a holetransporting material, the first organic layer is a hole transportlayer, the second organic material is a red emitting material, and thesecond organic layer and the third organic layer are a red emissivelayer.
 13. The method of claim 10, wherein the first organic material isa hole transporting material, the first organic layer is a holetransport layer, the second organic material is a green emittingmaterial, and the second organic layer and the third organic layer are agreen emissive layer.
 14. The method of claim 10, wherein the firstorganic material is a hole transporting material, the first organiclayer is a hole transport layer, the second organic material is a blueemitting material, and the second organic layer and the third organiclayer are a blue emissive layer.
 15. The method of claim 10, wherein thefirst organic material is a red emitting material, the first organiclayer is a red emissive layer, the second organic material is anelectron transporting material, and the second organic layer and thethird organic layer are an electron transport layer.
 16. The method ofclaim 10, wherein the first organic material is a green emittingmaterial, the first organic layer is a green emissive layer, the secondorganic material is an electron transporting material, and the secondorganic layer and the third organic layer are an electron transportlayer.
 17. The method of claim 10, wherein the first organic material isa blue emitting material, the first organic layer is a blue emissivelayer, the second organic material is an electron transporting material,and the second organic layer and the third organic layer are an electrontransport layer.
 18. The method of claim 10, wherein the first organicmaterial is an electron transporting material, the first organic layeris an electron transport layer, the second organic material is anelectron injecting material, and the second organic layer and the thirdorganic layer are an electron injection layer.